Objectives Construct a battery powered by a lemon. Observe and measure electrical voltage. Observe polarity(+, -) Analyze and discuss observations and data with other students. Relate findings to principles of electrochemistry.
Procedure Insert the penny and the nail into the lemon on opposite sides of the lemon. Push them in about 1/2 inch.
Procedure Attach a wire to the penny and one to the nail
Procedure Touch the other end of each wire to your tongue.
Procedure Measure the voltage across the lemon.
Procedure Use the Lemon Battery to light an LED, you may need help from other groups.
BATTERY BASICS The lemon juice allows the metal plates to gain or lose electrons. Then, those electrons travel over to the other plate. ( Zn lose e- / Cu gains e- ) The reaction creates a different electrical potential on the two different plates, so connecting them shows a voltage difference. e-
Objective The purpose of this experiment is to determine the relationship between pressure and volume of a gas at constant temperature.
Procedure A Pull the plunger all the way out. Put your finger on the end. Place the plunger back into the syringe and push the plunger in as hard as you can. It gets (easier, harder) to push the plunger in as you decrease the gas volume.
Procedure B Push the plunger all the way in. Put your finger on the end. Attempt to remove the plunger from the syringe. Is it difficult to remove the plunger?
Questions In general, how do gas molecules create pressure upon their container? (What are the molecules doing?) In Procedure A, when you compressed the plunger, it got more and more difficult to push the plunger in. Explain why. (Discuss molecules and collisions) In Procedure B, you found that it was difficult to pull the plunger out. Why was it so difficult? (What force is responsible? Hint: vacuum is not a force)